Use of Diluted 0,5 % H3PO4 for Two-stage Phosphoric Sulfite Pulping

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UDС

676.1.022

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Abstract

In order to improve ecology and economy of pulp production by two-stage phosphoric sulfite pulping, there has been revealed a possibility of reducing the concentration of H3PO4 for the second stage of cooking from 1,0 to 0,5 % H3PO4. It turned out that the decrease of acid concentration had a minor effect on characteristics of pulp and liquor. Pulp from phosphoric sulfite pulping differed from other sulfite pulps by higher yield, brightness and breaking length. Spectroscopic analysis of the spent liquor has shown that dissolved lignin in the new method of cooking has a low average molecular weight and is barely prone to secondary condensation. This condition makes it easier to recycle it, for example, as an agricultural fertilizer.

Authors

R.E. Smirnov Saint Petersburg State Technological University of Plant Polymers

Affiliation

Saint Petersburg State Technological University of Plant Polymers

Keywords

Key words: sulfite pulp, diluted solution of phosphoric acid for pulp production, two-stage phosphoric sulfite pulping method.